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UNiTnn PATENT Tries.

ROBERT V. LESLEY AND DAVID GRIFFITHS, OF PHILADE'LFHIA, .l?.'\..

MANUFACTURE OF PORTLAND CEMENT.

IJPEC'IFICATI ON forming part of Letters Patent No. 305,754, dated September 30,1884.

Application filed March 3, 1884.

To a whom it may concern- Be it known that we, ROBERT W. LnsLEY and DAVID GRIFFITHS, of the city and county of Philadelphia, State of Pennsylvania, have invented a new and useful Improvement in the Art of hilanufacturing Portland Cement, of which the following is a specification.

Portland cement is manufactured from clay and chalk, or limestone and clay, and is made by either the wet or dry process, both of which processes are well known to those skilled in the industry, the manu'tactured article containing by chemical analysis about seventy per cent. of lime to about thirty per cent. of silica and alumina, and also varying proportions of ferric oxide, soda, potash, and sulphuric acid. WVhile the manufacture has been attended with success in Europe, where the materials are easily obtainable, the industry has not attained a large growth in this country, owing to the difficulty of finding the raw materials advantageouslysituated and within close reach of each other.

Iron-furnaces in this country have usually been located in limestone regions, with aview to obtaining an economical supply 0 hat material fpnflpxing Pillp QfiQSQitHddlhQSG urnaces produce constaiitlyifimense quantities of iron slag or cinder whichhitherto has gone to 'aste, and has been piled in vast dumps at great cost in labor and storage. The slag,which is ejected from the furnaces at a very high temperature,

we have found to contain many of the elements necessary for the manufacture of Portland ccment, although largely deficient in lime for that purpose.

The object of our invention is the utilization of this slap' or cinder in the manufacture of Portlandeiimenuand this we have found can be accomplished by the gomhination with it of lime, 021L111}? and magnesia, in any of their Finis-whether hydrates, anhydrous earbonates, cement-rocks, or hydrauliclimcstone in such proportion as to bring the percentage of lime or lime and magnesia to about seventy per cent. of the manufactured cement and the proportions of silica and alumina to about thirty per cent. of the same. e may at times add to the combination a small. proportion of other silicates or hydrosilicates, taking care,

(No specimens.)

of this mixture. The product thus obtained is treated according to the wet or dry process, as desired; and we find that we can in this way produce a cement having all the characteris more, possessing advantages over the cements now made in strength, regularity, and economy of manufacture.

magnesia in any of their forms--whether hydrates, anhydrous carbonates, hydraulic limestone, or cement-rocks-eand ascertain to what extent they are deficient in silica and alumina.

has become cracked, broken, and partially pulverized,and, first ascertaining by analysis its constituent parts, add it to the mass before mentioned in which by long exposure to Tlifiarr lime or lime and magnesia in the manufactured cement to about seventy per cent. or say from fifty to sixty or seventy per cent.) and the percentage of silica and alumina to about thirty five per centtl The compound thus obtained is thoroughly intermixed, is ground together by either the wet or the dry process. is made into bricks or other forms suitable for the kilns,

maiuifactured ce ment.

Another way of carrying our invent-ioninto practice is to take lime, or lime and magnesia in any of their forms, as above stated, and,

obtained is deficient in silica and alumina, add to it slag or cinder which has been wetted while still hot (first ascertaining its composition, as above provided) in such proportions alumina in the manufactured cement substan tially as above stated, the object of wetting the slag or cinder as it is drawn from the furnace being to make it porous and spongy, and consequently easy to crush and grind. The ma 100 or cinder still remain the essential ingredients 5 5 tics of the best Portland cement, and, further- One way of carrying ourin ventioninto practice is as follows: \Ve take lime, or lime and hen this is done, we take iron slag or cinder,

such proportions as to bring the percentage of 7 5 per cent. (or say from twenty-five to thirty calcined to a clinker, and then ground into the after ascertaining to what extent the mass thus 0 as to bring the percentage of lime, silica, and 9 5 2 sows i terials are then ground all together, wetted, molded into forms, calcined into clinker, and ground again into the manufactured cement.

We desire to be understood that we intend to include within the terms of our claims all of the foregoingrecited methods of applying and using iron slag or cinder for the purpose of manufacturing Portland cement; but do not mean, however, to restrict ourselves to them alone.

Having now described our invention and the best ways known to us of carrying the same into practical effect, we state our claims as i'ollows:

1. The process of inanul'acturing Portland cement, consisting in combining with lime, or lime and magnesia in any of their lorms, as stated, iron slag or e'nder in substantially the proportions specified, and subsequently cal- 2. The hereinbeiore-described method of utiliziug iron slag or cinder in the manufac ture of Ylvortland cement, consisting in wetting or moistening the slag or cinder after it comes from the furnace and while still hot, so as to bring it to a condition in which it can be easily disintegrated, then combining the same with lime, or lime and magnesia in any oftheir forms, as stated, in substauti ally the proportions specilied, and subscquen tl y calcining said compound to a clinker and. grinding the same, substantially as set forth.

3. The hereinbei'ore-described product obtained, substantially in the manner set forth, from a mixture whereof lime, or lime and magnesia in any of their forms, as stated, and iron slag or cinder are essential ingredients, in substantiall y the proportions specified.

in testimony whereof we have hereunto set our hands this 29th day of February, 1884.

R. \V. LESLEY. DAX H) GRIFFITHS.

\Yitnesses:

E. H. ("rASKILL, l H, DoYLu. 

